Anastomosis is a procedure where two separate tubular or hollow organs are surgically grafted together to form an intercommunication between them. Vascular anastomosis involves creating an anastomosis between blood vessels to create or restore blood flow. The vascular anastomosis procedure is routinely performed during the treatment of a variety of conditions, including coronary artery disease (CAD), neurovascular disease, diseases of the great and peripheral vessels, organ transplantation, and traumatic injury. When a patient suffers from CAD, an occlusion or stenosis in a coronary artery restricts blood flow to the heart muscle. To treat CAD, the area where the occlusion occurs is bypassed to reroute blood flow by placing a graft vessel (in the form of a harvested artery or vein, prosthesis, allograft or xenograft) between two target vessels: the aorta or other supply of arterial blood, and the coronary artery. Placement of the graft vessel bypasses the blocked coronary artery, circumventing the occlusion and restoring adequate blood flow to the heart muscle. This treatment is known as a coronary artery bypass graft procedure (CABG). A CABG procedure can be performed on a stopped heart, where the patient has been placed on a heart-lung machine, or on a beating heart. Access to the thoracic cavity for a CABG procedure can be provided by sawing the sternum and opening the chest, or by creating one or more small openings in the thoracic cavity. Anastomosis may be performed by hand-suturing the graft vessels together or by utilizing an anastomosis device.
Regardless of the type of CABG procedure that is performed, or the type of anastomosis performed, an opening is made in the aorta or other artery at the proximal anastomosis site to allow blood to flow into the graft vessel. Typically, an incision is made in the aorta with a scalpel. A distal end of an aortic punch is inserted into the incision, then actuated to cut a larger opening in the aorta. While the combination of the scalpel and the aortic punch is commonly used to form an opening in the aorta, there are drawbacks. Between the time the incision is made and the time the aortic punch is used, it is difficult to maintain hemostasis. For example, the surgeon may place a finger over the incision after it is made. This is a problematic approach that does not provide reliable hemostasis during beating heart surgery, and has the potential to allow the location of the incision to become lost. Further, after the aortic punch creates an opening in the aorta, blood will flow out of that opening.
Other tools for creating an opening in a blood vessel wall utilize piercing members in conjunction with a cutter, where the piercing member and cutter are free to move relative to one another, and are actuated separately. The piercing member is generally deployed first, followed by the cutter. However, such an arrangement of the piercing member and the cutter can have difficulties in successfully creating a smooth opening in the blood vessel wall, and can have problems in retaining the tissue plug after it is removed from the blood vessel wall. Further, such an arrangement of the piercing member and cutter can be mechanically complex to implement.